JP2014013206A - Ultrasonic measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrasonic measuring device capable of reducing influences caused from self-noises by extending transmission interval even when a zero flow change occurs due to temperature changes.SOLUTION: An ultrasonic measuring device includes: a flow-rate calculating unit 9 that calculates a flow rate of a fluid to be measured based on a propagation time difference in ultrasonic transmission time to calculate an instantaneous flow rate from the flow rate; a temperature measuring unit 10 that measures a temperature of the fluid to be measured; an interval correction unit 11 that calculates the correlation between a flow rate value calculated by the flow-rate calculating means 9 in a state the fluid to be measured does not flow and the temperature measured by the temperature measuring unit 10 to control a repetition unit 7 to extend the intervals of repetition of the ultrasonic transmission between the oscillators when the flow rate value changes periodically as the temperature changes. With this, a precise ultrasonic measuring device capable of automatically correcting even when the flow rate value varies caused from self vibrations or self-noises of an ultrasonic oscillator due to temperatures changes in the ambient and/or the fluid to be measured can be provided.

Description

  The present invention relates to an ultrasonic measurement apparatus that measures the flow rate and flow velocity of a gas or liquid using ultrasonic waves.

  Conventionally, this type of ultrasonic measurement apparatus calculates a flow rate by correcting a flow rate measured in a state where a fluid to be measured is not flowing as a zero flow rate correction value at the time of actual flow rate calculation (for example, Patent Document 1). reference).

  FIG. 5 shows a conventional configuration described in Patent Document 1. In FIG. As shown in FIG. 5, the first vibrator 109 and the second vibrator 110 that transmit and receive sound waves, the channel time measuring means 111 that measures the propagation time of sound waves, and the flow rate are detected from the propagation time of the channel time measuring means 111. The flow rate detecting means 112 for performing vibration, the vibration coupling means 113 for acoustically coupling the vibration means, the vibration timing means 120 for measuring the vibration propagation time using a signal transmitted through the vibration coupling means 113, and the flow rate zero of the flow rate detecting means 112. The zero point adjusting means 114 is configured to adjust the zero point.

  Thus, the flow rate detection process equivalent to the process when the zero flow rate correction is zero flow rate can be performed using the vibration signal of the vibration transmitting means, so that the flow rate value can be calculated with high accuracy.

Japanese Patent Laid-Open No. 10-239126

  However, in the conventional configuration, when the propagation time between the transducers changes due to changes in the outside air temperature or the temperature of the fluid to be measured from the temperature at which the zero flow rate correction value is calculated, the ultrasonic transducer on the transmission side changes. Due to the influence of the self-vibration of the ultrasonic transducer during transmission and the self-noise in the internal circuit of the transmission means, the ultrasonic propagation time will be deviated from the zero flow rate correction, and the accuracy of the flow rate calculation result will deteriorate. High-precision measurement was difficult.

  The present invention solves the above-described problem. Even if the self-vibration of the ultrasonic vibrator or the self-noise of the internal circuit occurs without being affected by the temperature of the outside air or the fluid to be measured, the ultrasonic signal at the time of reception is obtained. It is an object of the present invention to provide a highly accurate ultrasonic measurement apparatus that can efficiently measure without adverse effects.

In order to solve the above-described conventional problems, an ultrasonic measurement apparatus according to the present invention includes a first vibrator and a second vibrator that are provided in a fluid conduit through which a fluid to be measured flows, and that transmit and receive ultrasonic waves. Transmission / reception switching means for the second vibrator, repetitive means for performing ultrasonic transmission between the first and second vibrators a plurality of times at regular time intervals, and ultrasonic propagation between the first and second vibrators Time measuring means for measuring time, ultrasonic propagation time from the first vibrator to the second vibrator and ultrasonic propagation time from the second vibrator to the first vibrator measured by the time measuring means. The flow rate of the fluid to be measured is calculated from the propagation time difference, the flow rate calculating means for calculating the instantaneous flow rate value from the flow rate, the temperature measuring means for measuring the temperature of the fluid to be measured, and the flow rate when the fluid to be measured is not flowing. The flow rate value Q0 calculated by the calculation means and the thermometer When the correlation between the temperatures measured by the means is calculated, and the flow rate value Q0 fluctuates periodically with changes in temperature, the repetition time of the ultrasonic transmission between the transducers performed by the repetition means And interval correction means for extending the interval.

  As a result, the next transmission signal can be output after the reverberation of self-vibration or self-noise that had changed the ultrasonic reception has subsided, and even if self-vibration or self-noise occurs, an accurate flow rate value can be measured. it can.

  According to the ultrasonic measurement apparatus of the present invention, even if the outside air temperature or the temperature of the fluid to be measured changes, and the flow rate fluctuation due to the self vibration or self noise of the ultrasonic vibrator occurs, it can be automatically corrected, and the higher accuracy. An ultrasonic measurement apparatus can be provided.

1 is a block diagram of an ultrasonic measurement apparatus according to Embodiment 1 of the present invention. Block diagram of an ultrasonic measurement apparatus according to Embodiment 2 of the present invention Block diagram of an ultrasonic measurement apparatus according to Embodiment 3 of the present invention Block diagram of an ultrasonic measurement apparatus according to Embodiment 4 of the present invention Block diagram of a conventional ultrasonic measurement device

  According to a first aspect of the present invention, there are provided a first vibrator and a second vibrator, which are provided in a fluid conduit through which a fluid to be measured flows, transmit / receive ultrasonic waves, transmission / reception switching means of the first and second vibrators, 1. Repetitive means for performing ultrasonic transmission between the second vibrators a plurality of times at regular time intervals, time measuring means for measuring the ultrasonic propagation time between the first and second vibrators, and measurement by the time measuring means Calculating the flow velocity of the fluid to be measured from the difference in propagation time between the ultrasonic propagation time from the first vibrator to the second vibrator and the ultrasonic propagation time from the second vibrator to the first vibrator; A flow rate calculation means for calculating an instantaneous flow rate value from the flow velocity, a temperature measurement means for measuring the temperature of the fluid to be measured, a flow rate value Q0 calculated by the flow rate calculation means in a state where the fluid to be measured is not flowing, and the temperature measurement Calculate the correlation of the temperature measured by the means, Interval correction means for extending the time interval of repeated ultrasonic transmission between the transducers performed by the repetition means when the flow rate value Q0 periodically fluctuates with a change in degree. As a result, the next transmission signal can be output after the reverberation of self-vibration and self-noise that had caused changes in ultrasonic reception has subsided. Even if flow rate fluctuations due to self-vibration or self-noise occur, it can be automatically corrected, enabling more accurate ultrasonic measurement.

  In a second aspect of the invention, in particular, in the first aspect of the invention, the time measuring means uses a counter whose period changes according to the ambient temperature, and the temperature measuring means determines the temperature of the fluid to be measured from the period of the counter. With the calculation configuration, the temperature of the fluid to be measured is calculated by increasing or decreasing the frequency when the temperature changes, and it is determined whether the instantaneous flow rate value in the zero flow rate state varies periodically with temperature. It is possible to measure temperature without attaching a temperature measuring device such as a thermometer, even if the temperature of the fluid to be measured changes and the flow rate value fluctuations occur due to self-vibration or self-noise of the ultrasonic vibrator. It can be corrected automatically, and more accurate ultrasonic measurement can be performed.

In a third aspect of the invention, in particular, in the first aspect of the invention, the temperature measuring means calculates the temperature of the fluid to be measured from the ultrasonic propagation time measured by the time measuring means in a state where the fluid to be measured is not flowing. By calculating the outside air temperature and the temperature of the fluid to be measured by increasing or decreasing the propagation time when the temperature changes, it is determined whether the instantaneous flow rate value in the zero flow state fluctuates periodically depending on the temperature. Yes, it can measure temperature without attaching a temperature measuring device such as a thermometer, and even if the temperature of the fluid to be measured changes and the flow rate fluctuations due to self-vibration or self-noise of the ultrasonic transducer occur Correction can be performed with a more accurate ultrasonic measurement.

  In a fourth aspect of the present invention, in particular, in any one of the first to third aspects, the interval correction unit is configured to measure the flow rate value Q0 calculated by the flow rate calculation unit and the temperature measurement in a state where the fluid to be measured is not flowing. The temperature of the fluid to be measured measured by the means is compared in time series, and when the flow rate value Q0 does not fluctuate periodically according to the temperature change, the ultrasonic transmission between the transducers performed by the repetitive means is performed. By adopting a configuration that shortens the repetition time interval, it is possible to shorten the total repetition time of ultrasonic transmission / reception and shorten the operation time of the control circuit unit. Therefore, more accurate ultrasonic measurement can be performed while suppressing current consumption.

  Hereinafter, a mounting configuration of an ultrasonic transducer according to an embodiment of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 shows an ultrasonic measurement apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, a first vibrator 1 and a second vibrator 2 that transmit and receive ultrasonic waves are arranged in the middle of a fluid conduit 3 through which a fluid to be measured flows, and are arranged at a distance in the flow direction. Transmission / reception of the first vibrator 1 and the second vibrator 2 is switched.

  First, the switching means 8 selects the first vibrator 1 as a transmission side and the second vibrator 2 as a reception side, the transmission means 4 performs a transmission output to the first vibrator 1, and the reception means 5 The signal of the second vibrator 2 that has received the ultrasonic signal transmitted from the first vibrator is received, and the time from the first vibrator 1 to the second vibrator 2 is set as the ultrasonic propagation time by the time measuring means 6. taking measurement.

  The repeater 7 delays for a specified time after being transmitted from the transmitter 4, instructs again to transmit from the transmitter 4, and when it is output again from the transmitter 4, the first vibration is generated by the switching unit 8. The transmission / reception of the child 1 and the second vibrator 2 is switched to transmit an ultrasonic signal from the second vibrator 2, the ultrasonic signal is received by the first vibrator 1, and this transmission is repeated as described above.

  The flow rate calculation means 9 sets the ultrasonic propagation time measured by setting the first vibrator 1 measured on the transmission means 6 on the transmission side and the ultrasonic propagation time measured by setting the second vibrator 2 on the transmission side. The flow velocity of the fluid to be measured is calculated from the propagation time difference, and the instantaneous flow rate value of the fluid to be measured is calculated from the flow velocity.

  Further, the temperature measuring means 10 is a temperature sensor attached in the fluid conduit 3, and the interval correcting means 11 is a flow rate value Q0 (hereinafter, zero flow rate value) calculated by the flow rate calculating means 9 when the fluid to be measured is not flowing. And the temperature measured by the temperature measuring means 10 are compared, and if the flow rate value periodically fluctuates with the temperature, the repeater 7 is instructed to extend the transmission and the transmission time delay. To do.

  The operation and action of the ultrasonic measuring apparatus configured as described above will be described below.

  First, in order to output the first transmission signal from the first vibrator 1, the signal is transmitted from the transmission means 4 to the switching means 8 and transmitted to the first vibrator 1 by the switching means 8. The ultrasonic signal output from the first vibrator 1 is received by the second vibrator 2 for the first time and is transmitted to the receiving means 5 through the switching means 8.

Thereafter, the ultrasonic propagation time from the upstream side to the downstream side, which is the time from the transmission of the first transducer 1 to the reception of the second transducer 2, is measured by the timing unit 6 through the repeating unit 7. At the first reception, the repeater 7 counts the delay until the second transmission for a specified time, and outputs the second transmission to the transmitter 4 when the specified time is reached. In the second time, the switching means 8 transmits a transmission signal to the second transducer 2 in order to transmit ultrasonic waves from the second transducer 2 to the first transducer 1 from the downstream side.

  In this manner, ultrasonic transmission / reception is repeated with a predetermined time delay to measure the ultrasonic propagation time from the upstream side of the fluid conduit 3 and the ultrasonic propagation time from the downstream side.

  Next, the flow rate calculation means 9 calculates the flow rate value at the moment when the ultrasonic waves are transmitted from the difference between the ultrasonic propagation time from the upstream and the ultrasonic propagation time measured by the time measuring means 6.

  Then, in order to verify whether the instantaneous flow rate value continuously measured by the flow rate calculation means 9 has an error due to self noise or the like, first, a temperature sensor attached in the fluid conduit of the temperature measurement means 10 is used. The temperature of the fluid to be measured is measured, and at the same time, the fluid to be measured is shut off by a valve (not shown) or the like, and the zero flow rate value is measured by the flow rate calculation means 9 when the flow rate is zero.

  In the interval correction means 11, the temperature measured as described above and the zero flow rate value are compared with the zero flow rate value with respect to the absolute temperature, and it is determined whether or not a regular flow rate value change is observed with the temperature change. If there is a change in the flow rate value, it is determined that it is affected by noise, and the repeater 7 is instructed to set the time further extended than the currently set delay time. The interval of sound wave transmission is extended.

  As described above, in the present embodiment, the temperature of the fluid to be measured is measured by the temperature measuring means 10, and if there is a change in the flow rate value with respect to the absolute temperature by the interval correcting means 11, it is determined that it is affected by noise. By extending the interval of ultrasonic transmission, the next ultrasonic transmission can be performed after the noise is attenuated without being affected by self-noise, etc., and noise interference of the received signal can be reduced. Even if the temperature of the fluid to be measured changes, it can be automatically corrected, and more accurate ultrasonic measurement can be performed.

(Embodiment 2)
FIG. 2 shows an ultrasonic measurement apparatus according to Embodiment 2 of the present invention.

  In FIG. 2, a first vibrator 1 and a second vibrator 2 that transmit and receive ultrasonic waves are arranged in the middle of a fluid conduit 3 through which a fluid to be measured flows. Transmission / reception of the first vibrator 1 and the second vibrator 2 is switched.

  First, the switching means 8 selects the first vibrator 1 as a transmission side and the second vibrator 2 as a reception side, the transmission means 4 performs a transmission output to the first vibrator 1, and the reception means 5 The signal from the second vibrator 2 that has received the ultrasonic signal transmitted from the first vibrator is received, and the time measuring means 6 uses the counter 12 that can measure the time at a constant frequency, from the first vibrator 1 to the second vibrator 2. Is measured as the ultrasonic propagation time.

  The repeater 7 gives a command to send again from the transmitter 4 after a predetermined time delay from the transmitter 4, and when it is output from the transmitter 4 again, the switching unit 8 causes the first vibrator The transmission / reception of the first vibrator 2 and the second vibrator 2 is switched to transmit an ultrasonic signal from the second vibrator 2, the ultrasonic signal is received by the first vibrator 1, and this transmission is repeated as described above.

  The flow rate calculation means 9 sets the ultrasonic propagation time measured by setting the first vibrator 1 measured on the transmission means 6 on the transmission side and the ultrasonic propagation time measured by setting the second vibrator 2 on the transmission side. The flow velocity of the fluid to be measured is calculated from the propagation time difference, and the instantaneous flow rate value of the fluid to be measured is calculated from the flow velocity.

Further, the temperature measuring means 10 converts the temperature of the fluid to be measured at that time from the frequency by using the characteristic that the frequency changes by a certain amount depending on the temperature of the counter 12, and the interval correcting means 11 calculates the flow of the fluid calculated by the flow rate calculating means. When the zero flow rate value when not flowing and the temperature measured by the temperature measuring means 10 are compared, and the flow value fluctuates periodically with the temperature, the transmission and transmission time delays are given to the repeating means 7. Order to extend.

  The operation and action of the ultrasonic measuring apparatus configured as described above will be described below.

  First, in order to output the first transmission signal from the first vibrator 1, the signal is transmitted from the transmission means 4 to the switching means 8 and transmitted to the first vibrator 1 by the switching means 8. The ultrasonic signal output from the first vibrator 1 is received by the second vibrator 2 for the first time and is transmitted to the receiving means 5 through the switching means 8.

  After that, the time from the transmission of the first vibrator 1 to the reception of the second vibrator 2 is measured by the counter 12 of the time measuring means 6 through the repeating means 7 and the period of a constant frequency is measured, and from the upstream side to the downstream side. Measure the ultrasonic propagation time. At the first reception, the repeater 7 counts the delay until the second transmission for a specified time, and outputs the second transmission to the transmitter 4 when the specified time is reached. In the second time, the switching means 8 transmits a transmission signal to the second transducer 2 in order to transmit ultrasonic waves from the second transducer 2 to the first transducer 1 from the downstream side.

  In this manner, ultrasonic transmission / reception is repeated with a predetermined time delay to measure the ultrasonic propagation time from the upstream side of the fluid conduit 3 and the ultrasonic propagation time from the downstream side.

  Next, the flow rate calculation means 9 calculates the flow rate value at the moment when the ultrasonic waves are transmitted from the difference between the ultrasonic propagation time from the upstream and the ultrasonic propagation time measured by the time measuring means 6.

  Then, in order to verify whether the instantaneous flow rate value continuously measured by the flow rate calculation means 9 has an error due to self-noise, the temperature measurement means 10 first measures the frequency of the counter 12, and this frequency is the temperature. Because of this, a certain amount of frequency change occurs, so that the temperature of the fluid to be measured can be estimated from the frequency. Thus, the temperature of the fluid to be measured is measured, and at the same time, the fluid to be measured is shut off by a valve (not shown) or the like, and the zero flow value is measured by the flow rate calculation means 9 in a state where the flow rate value is zero.

  The interval correction unit 11 compares the temperature measured as described above with the zero flow rate value, and the interval correction unit 11 compares the zero flow rate value with respect to the absolute temperature, and the change in the flow rate value with regularity is changed with the temperature change. If there is a change in the flow rate value, it is determined that it is affected by noise, and the repeater 7 is instructed to set the time further longer than the currently set delay time. The interval of the next ultrasonic transmission is extended.

  As described above, in the present embodiment, the temperature of the fluid to be measured is measured by the temperature measuring means 10, and if there is a change in the flow rate value with respect to the absolute temperature by the interval correcting means 11, it is determined that it is affected by noise. By extending the interval of ultrasonic transmission, the next ultrasonic transmission can be performed after the noise is attenuated without being affected by self-noise, etc., and noise interference of the received signal can be reduced. Even if the temperature of the fluid to be measured changes, it can be automatically corrected, and more accurate ultrasonic measurement can be performed.

(Embodiment 3)
FIG. 3 shows an ultrasonic measurement apparatus according to Embodiment 3 of the present invention.

In FIG. 3, a first vibrator 1 and a second vibrator 2 that transmit and receive ultrasonic waves are arranged in the middle of a fluid conduit 3 through which a fluid to be measured flows. Transmission / reception of the first vibrator 1 and the second vibrator 2 is switched.

  First, the switching means 8 selects the first vibrator 1 as a transmission side and the second vibrator 2 as a reception side, the transmission means 4 performs a transmission output to the first vibrator 1, and the reception means 5 The signal of the second vibrator 2 that has received the ultrasonic signal transmitted from the first vibrator is received, and the time measuring means 6 uses the time from the first vibrator 1 to the second vibrator 2 as the propagation time of the ultrasonic wave. taking measurement.

  The repeater 7 gives a command to send again from the transmitter 4 after a predetermined time delay from the transmitter 4, and when it is output from the transmitter 4 again, the switching unit 8 causes the first vibrator The transmission / reception of the first vibrator 2 and the second vibrator 2 is switched to transmit an ultrasonic signal from the second vibrator 2, the ultrasonic signal is received by the first vibrator 1, and this transmission is repeated as described above.

  The flow rate calculation means 9 sets the ultrasonic propagation time measured by setting the first vibrator 1 measured on the transmission means 6 on the transmission side and the ultrasonic propagation time measured by setting the second vibrator 2 on the transmission side. The flow velocity of the fluid to be measured is calculated from the propagation time difference, and the instantaneous flow rate value of the fluid to be measured is calculated from the flow velocity.

  Further, the temperature measuring means 10 converts the temperature of the fluid to be measured at that time from the temperature characteristic of the propagation time measured by the time measuring means 6, and the interval correcting means 11 is zero when the fluid does not flow calculated by the flow rate calculating means. The flow rate value is compared with the temperature measured by the temperature measuring means 10, and when the flow value fluctuates periodically with the temperature, the repeater 7 is instructed to extend the transmission and transmission time delay. To do.

  The operation and action of the ultrasonic measuring apparatus configured as described above will be described below.

  First, in order to output the first transmission signal from the first vibrator 1, the signal is transmitted from the transmission means 4 to the switching means 8 and transmitted to the first vibrator 1 by the switching means 8. The ultrasonic signal output from the first vibrator 1 is received by the second vibrator 2 for the first time and is transmitted to the receiving means 5 through the switching means 8.

  Thereafter, the ultrasonic propagation time from the upstream side to the downstream side, which is the time from the transmission of the first transducer 1 to the reception of the second transducer 2, is measured by the timing unit 6 through the repeating unit 7. At the first reception, the repeater 7 counts the delay until the second transmission for a specified time, and outputs the second transmission to the transmitter 4 when the specified time is reached. In the second time, the switching means 8 transmits a transmission signal to the second transducer 2 in order to transmit ultrasonic waves from the second transducer 2 to the first transducer 1 from the downstream side.

  In this manner, ultrasonic transmission / reception is repeated with a predetermined time delay to measure the ultrasonic propagation time from the upstream side of the fluid conduit 3 and the ultrasonic propagation time from the downstream side.

  Next, the flow rate calculation means 9 calculates the flow rate value at the moment when the ultrasonic waves are transmitted from the difference between the ultrasonic propagation time from the upstream and the ultrasonic propagation time measured by the time measuring means 6.

  In order to verify whether the instantaneous flow rate value continuously measured by the flow rate calculation means 9 has an error due to self-noise or the like, first, the fluid to be measured is shut off by a valve (not shown) or the like, and the flow rate value is zero. In this state, the flow rate calculation means 9 measures the zero flow rate value. The propagation time measured by the time measuring means 6 by the temperature measuring means 10, and this propagation time changes by a certain amount depending on the temperature, so that the temperature of the fluid to be measured can be estimated. As a result, the temperature of the fluid to be measured is measured, and the zero flow rate value of the fluid to be measured is measured at the same time.

The interval correction unit 11 compares the temperature measured as described above with the zero flow rate value, and the interval correction unit 11 compares the zero flow rate value with respect to the absolute temperature, and the change in the flow rate value with regularity is changed with the temperature change. If there is a change in the flow rate value, it is determined that it is affected by noise, and the repeater 7 is instructed to set the time further longer than the currently set delay time. The interval of the next ultrasonic transmission is extended.

  As described above, in the present embodiment, the temperature of the fluid to be measured is measured by the temperature measuring means 10, and if there is a change in the flow rate value with respect to the absolute temperature by the interval correcting means 11, it is determined that it is affected by noise. By extending the interval of ultrasonic transmission, the next ultrasonic transmission can be performed after the noise is attenuated without being affected by self-noise, etc., and noise interference of the received signal can be reduced. Even if the temperature of the fluid to be measured changes, it can be automatically corrected, and more accurate ultrasonic measurement can be performed.

(Embodiment 4)
FIG. 4 shows an ultrasonic measurement apparatus according to Embodiment 1 of the present invention.

  In FIG. 4, a first vibrator 1 that transmits and receives ultrasonic waves and a second vibrator 2 that receives ultrasonic waves are arranged in the middle of a fluid conduit 3 through which a fluid to be measured flows, and is arranged at a distance in the flow direction. Thus, transmission / reception of the first vibrator 1 and the second vibrator 2 is switched.

  First, the switching means 8 selects the first vibrator 1 as a transmission side and the second vibrator 2 as a reception side, the transmission means 4 performs a transmission output to the first vibrator 1, and the reception means 5 The signal of the second vibrator 2 that has received the ultrasonic signal transmitted from the first vibrator is received, and the time from the first vibrator 1 to the second vibrator 2 is set as the ultrasonic propagation time by the time measuring means 6. taking measurement.

  The repeater 7 gives a command to send again from the transmitter 4 after a predetermined time delay from the transmitter 4, and when it is output from the transmitter 4 again, the switching unit 8 causes the first vibrator The transmission / reception of the first vibrator 2 and the second vibrator 2 is switched to transmit an ultrasonic signal from the second vibrator 2, the ultrasonic signal is received by the first vibrator 1, and this transmission is repeated as described above.

  The flow rate calculation means 9 sets the ultrasonic propagation time measured by setting the first vibrator 1 measured on the transmission means 6 on the transmission side and the ultrasonic propagation time measured by setting the second vibrator 2 on the transmission side. The flow velocity of the fluid to be measured is calculated from the propagation time difference, and the instantaneous flow rate value of the fluid to be measured is calculated from the flow velocity.

  The temperature measuring means 10 is a temperature sensor attached in the fluid conduit 3, and the interval correcting means 11 is the zero flow rate value calculated when the flow rate calculating means is not flowing and the temperature measured by the temperature measuring means 10. Are compared to determine whether or not the flow value fluctuates periodically with temperature, and the repeater 7 is instructed to extend or shorten the time delay between transmission and transmission. The control circuit unit 13 performs this series of controls.

  The operation and action of the ultrasonic measuring apparatus configured as described above will be described below.

  First, in order to output the first transmission signal from the first vibrator 1, the signal is transmitted from the transmission means 4 to the switching means 8 and transmitted to the first vibrator 1 by the switching means 8. The ultrasonic signal output from the first vibrator 1 is received by the second vibrator 2 for the first time and is transmitted to the receiving means 5 through the switching means 8.

  Thereafter, the ultrasonic propagation time from the upstream side to the downstream side, which is the time from the transmission of the first transducer 1 to the reception of the second transducer 2, is measured by the timing unit 6 through the repeating unit 7. At the first reception, the repeater 7 counts the delay until the second transmission for a specified time, and outputs the second transmission to the transmitter 4 when the specified time is reached. In the second time, the switching means 8 transmits a transmission signal to the second transducer 2 in order to transmit ultrasonic waves from the second transducer 2 to the first transducer 1 from the downstream side.

  In this manner, ultrasonic transmission / reception is repeated with a predetermined time delay to measure the ultrasonic propagation time from the upstream side of the fluid conduit 3 and the ultrasonic propagation time from the downstream side.

  Next, the flow rate calculation means 9 calculates the flow rate value at the moment when the ultrasonic waves are transmitted from the difference between the ultrasonic propagation time from the upstream and the ultrasonic propagation time measured by the time measuring means 6.

  Then, in order to verify whether the instantaneous flow rate value continuously measured by the flow rate calculation means 9 has an error due to self-noise or the like, first, a temperature sensor attached in the fluid conduit of the temperature measurement means 10 is used. The temperature of the measurement fluid is measured, and at the same time, the fluid to be measured is shut off by a valve (not shown) or the like, and the zero flow rate value is measured by the flow rate calculation means 9 in a state where the flow rate value is zero.

  The interval correction unit 11 compares the temperature measured as described above with the zero flow rate value, and the interval correction unit 11 compares the zero flow rate value with respect to the absolute temperature, and the change in the flow rate value with regularity is changed with the temperature change. If there is a change in the flow rate value, it is determined that it is affected by noise, and the repeater 7 is instructed to set the time further longer than the currently set delay time. The interval of the next ultrasonic transmission is extended. However, if there is no change in flow rate, it is determined that there is no influence of noise, and an instruction is given to repeatedly reduce the delay time.

  As described above, in the present embodiment, the temperature of the fluid to be measured is measured by the temperature measuring means 10, and if there is a change in the flow rate value with respect to the absolute temperature by the interval correcting means 11, it is determined that it is affected by noise. The interval of ultrasonic transmission is extended, but when the influence of self-noise, etc. disappears, the delay time is repeatedly shortened and the control time of the control circuit unit 13 can be shortened, so that power consumption can be reduced. It becomes. As a result, even if the outside air temperature or the temperature of the fluid to be measured changes, it can be automatically corrected, more accurate ultrasonic measurement can be performed, and if the influence of noise is reduced, it can be automatically switched to power consumption reduction control. is there.

  As described above, since the ultrasonic measurement device according to the present invention is highly reliable and highly accurate as a measurement device, it can be used in applications such as fluid measurement devices that require high reliability such as gas meters and water meters. Applicable.

DESCRIPTION OF SYMBOLS 1 1st vibrator | oscillator 2 2nd vibrator | oscillator 3 Fluid pipe line 4 Transmitting means 5 Receiving means 6 Time measuring means 7 Repeating means 8 Switching means 9 Flow rate calculating means 10 Temperature measuring means 11 Interval correction means 12 Counter 13 Control circuit part

Claims (4)

A first vibrator and a second vibrator, which are provided in a fluid conduit through which a fluid to be measured flows and transmit / receive ultrasonic waves;
A transmission / reception switching means for the first and second vibrators;
Repetitive means for performing ultrasonic transmission between the first and second vibrators a plurality of times at regular time intervals; and time measuring means for measuring ultrasonic propagation time between the first and second vibrators;
The flow velocity of the fluid to be measured is calculated from the difference in propagation time between the ultrasonic wave propagation time from the first vibrator to the second vibrator and the ultrasonic wave propagation time from the second vibrator to the first vibrator measured by the time measuring means. And a flow rate calculation means for calculating an instantaneous flow rate value from the flow velocity,
Temperature measuring means for measuring the temperature of the fluid to be measured;
The flow rate value Q0 calculated by the flow rate calculation means and the temperature measured by the temperature measurement means are calculated in a state where the fluid to be measured is not flowing, and the flow rate value Q0 periodically varies with a temperature change. And an interval correction unit for extending a time interval of repetition of ultrasonic transmission between the transducers performed by the repetition unit. The time measuring means has a configuration using a counter whose period changes according to the ambient temperature,
The ultrasonic measurement apparatus according to claim 1, wherein the temperature measurement unit is configured to calculate a temperature of a fluid to be measured from a cycle of the counter. The ultrasonic measurement apparatus according to claim 1, wherein the temperature measuring unit calculates the temperature of the fluid to be measured from the ultrasonic propagation time measured by the time measuring unit in a state where the fluid to be measured is not flowing. The interval correction means compares the flow rate value Q0 calculated by the flow rate calculation means with the temperature of the fluid to be measured measured by the temperature measurement means in a time series in a state where the fluid to be measured is not flowing, and changes the temperature. Accordingly, when the flow rate value Q0 does not fluctuate periodically, the repetition time interval of the ultrasonic transmission between the transducers performed by the repetition unit is shortened. The ultrasonic measurement apparatus described in 1.